2014/02/28 by Nadia L. Zakamska, Jenny E. Greene · 11 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Outflow #Physics #Quasar #Spectral line #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stu842
23 pages, accepted to MNRAS
arxiv created 2014/04/29 · openalex publication_date 2014/06/09 · arxiv updated 2015/06/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We analyse Sloan Digital Sky Survey spectra of 568 obscured luminous quasars. The [O iii] λ5007 Å emission line shows blueshifts and blue excess, indicating that some of the narrow-line gas is undergoing an organized outflow. The velocity width containing 90 per cent of line power ranges from 370 to 4780 km s−1, suggesting outflow velocities up to ∼2000 km s−1, and is strongly correlated with the radio luminosity among the radio-quiet quasars. We propose that radio emission in radio-quiet quasars is due to relativistic particles accelerated in the shocks within the quasar-driven outflows; star formation in quasar hosts is insufficient to explain the observed radio emission. The median radio luminosity of the sample of νLν[1.4 GHz] = 1040 erg s−1 suggests a median kinetic luminosity of the quasar-driven wind of Lwind = 3 × 1044 erg s−1, or about 4 per cent of the estimated median bolometric luminosity Lbol = 8 × 1045 erg s−1. Furthermore, the velocity width of [O iii] is positively correlated with mid-infrared luminosity, which suggests that outflows are ultimately driven by the radiative output of the quasar. Emission lines characteristic of shocks in quasi-neutral medium increase with the velocity of the outflow, which we take as evidence of quasar-driven winds propagating into the interstellar medium of the host galaxy. Quasar feedback appears to operate above the threshold luminosity of Lbol ∼ 3 × 1045 erg s−1.